Apache CXF 3.X已經移掉XMLUtils

http://cxf.apache.org/docs/30-migration-guide.html
Move ALL XML parsing and writing to StaxUtils and DOM based utilities to DOMUtils. The XMLUtils class that used SAX based parsing and Transformer based writing has been eliminated. This simplifies the code as well as increases security as we can provide better limits and have more control with the StAX based IO.

XMLUtils (Apache CXF Bundle Jar 2.7.0 API)
https://cxf.apache.org/javadoc/latest-2.7.x/org/apache/cxf/helpers/XMLUtils.html